Control



2 FIG.

l FIG.3

v @KWWL Aug. 31, 1948. G. c. PEARcE CONTROL Filed Dec.

Patented Aug. 31, 1948 CONTROL George C. Pearce, Dayton,

eral Motors Corporation, Dayton,

poration of Delaware Ohio, assigner to Gen- Ohio, a cor- Application December 11, 1944, Serial No. 567,696

This invention relates to controls, and more particularly to a switch adapted to control the energlzation of the heaters of an oven in an elec'- tric range or the like in respOnse to temperatures within the oven. The switch may also be used to control the energization of any electric circuit for any type of domestic appliance or the like.

An object of this invention is to provide a switch of simple construction, in which the parts are rugged and may be made with relatively large tolerances without affecting the efficiency of the switch.

yAnother object of this invention is to provide a simple control in which an extremely small dimensional change of the power element operates the snap action mechanism without any hesitation and with a high degree of accuracy.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a longitudinal'cross-section taken ,along the line l-I of Fig. 2;

Fig. 2 is a transverse cross-section taken along the line 2-2 of Fig. i; and

Fig. 3 is a cross-section taken along the line of Fig. 2.

A switch embodying features of my invention includes, in general, a first frame l0, conveniently channel-shaped in cross-section. It also includes a second frame I-l, conveniently also channelshaped in cross-section. Fulcrum means, in the form of a pin i2, holds the frames together at one end. Spring means are provided at the other end of the frame members I3 and Il. This spring means may comprise two helical coils I3, each mounted around the pins I4, which pins are secured to the first frame I3. The springs I3 urge the frame members Il and il away from each other, and tend to swing them apart, about the fulcrum I2. A rotatable shaft I5 is in threaded engagement at i3 with theframe I3, and is in axially fixed bearing engagement at l1 with the frame Il. This last bearing engagement includes a disc I8 fixed to the shaft l5. and bearing against the side of the frame Il. The springs I3 urge the frame Il against the distI I3. Rotation of the shaft l5 varies the angle between the frames in and I I, for the purpose of varying the temperature setting,l as hereinafter more fully explained. The shaft I3 may be rotated by a suitable manually actuatable knob, not shown, which may be secured 23 Claims. (Cl` 200-140) to the shaft I3 at the end I3. Such knob may carry suitable temperature indications.

A snap switch 20 is carried by the first frame i0. A thermostatic power element 1i is carried by the second frame l I and engages the snap acting switch at 22. The thermostatic power element 2| may be connected by a tube 23 with a liquid bulb, not shown, which may be placed in the oven to be heated by electric elements controlled by the switch 20. Expansion of the liquid in the bulb introduces liquid into the power element 2|, and expands the same. This -moves the point .24 against the lever 25, at 22,' ci the snap acting switch 23, and actuates the same. Manual rotation of the shaft l5 varies the angle between the frames I0 and Il, and varies or selects the temperature setting at which the snap switch 20 operates.

The snap switch 20 may include one or more snap acting U of these blades 30 has a first leg 3l secured to the frame III at 32. Each leg 3l is secured at 32 by means of a rivet, which in turn is secured to its respective conductor bar 33, which passes through a base 34 of insulating material, and terminates at 35. A respective connector 36threaded1y engages each bar 33. to which a respective electric line may be secured. Each bar 33 is also secured to the base 34 at 33a and 3l by means of rivets. The base 34 is carried by theframe I0, being secured thereto by screws 34a and bolts 44.

Each of the conductor blades 30 also has a second leg 33 which Ais in an on and off snapping engagement with a respective stationary contact 39, carried by the frame i0. Each contact 39 is carried by a respective conductor bar 40. Each bar 4l! passes through the base 34 and terminates atl 4I, where each bar 43 is provided with a connector 42 in threaded engagement with the bar 40. Each leg 33 is limited in its off position travel by a respective Z-bar 43, of insulating material. Each Z-bar 43 is secured to the frame I0 by the bolt u.

Thus, as shown, the thermostatic switch is a double pole switch, with'two input connectors 3B and two output connectors 42. f The number of poles may be varied, if desired.

The U-shaped conductor blades 30 are preferably formed of sheet metal, and the legs3l and 33, vtogether with their bridging member, are all of an integral piece of sheet metal.

Movable spring means are provided for creating a longitudinal compression strain in each of the legs 3l, for the purpose of producing on and off snap action in the second legs 33. Preferably this -shaped conductor blades 30. Each takes the form of a tension helical spring I. which is secured at one end to a metal bar 5I. which bar in turn is secured by rivets 5I to the bar 52 of insulating material.A The bar 52 is riveted at 53 to the blades 30, to cause them to move in unison. The other end of the spring 50 is secured to the lever at the orifice 54. The lever 25 is carried by the frame ill through the medium of an inverted U-shaped leaf spring 55 which is secured to the pins 56 by means of bolts 51. A relatively rigid U-shaped backing plate 55a is'lnterposed between the spring 55 and the pins 58. The pins 55 are secured to the frame IU by screws 58a. The spring 55 causes the lever 25 to fulcrum about the spring 55 with a bias towards the thermostatic power element 2|, whereas the power element 2 I, when it eipands, fulcrums the lever 25 in opposition to the spring 55.

When the lever 25 swings counterclockwise, in Fig. 1, due to cooling of the oven, or the likel the lever 25 reaches a point'where the upper end of the spring 50 and bar 52 snap to the left as indicated in dotted lines in Fig. l. This action causes the contacts 60, at the lower ends of legs 35, to move into contact with the respective stationary contacts 39 as indicated in dotted lines in Fig. 1. When this occurs, current can pass from each connector 36 through bars 33 and rivets 32 to the respective conductor blades Il. and from thence, through contacts 60, 39, bars 4|) and connectors -42 to the heaters in the oven which are then energized. The temperature at which this occurs is determined by the rotational position of shaft I5 and its manually actuatable knob. When the oven is heated to a predetermined upper limit, determined by the same position of shaft I5 and its knob, the liquid from the bulb yexpands power element 2| a suiiicient amount to swing the lever 25 clockwise, when the upper end of spring 50 is snapped to the right to move the bar 52 against the head of stop screw 6|. .This opens the contacts 60 away from the contacts 39. This deenergizes the heaters in the oven at the upper temperature limit.

By using member 43 as a stationary contact support, and making 43 of conducting material, while making 39 and 40 of insulating material, the switch may be used to control the operation of a refrigerator or the like, where electrical envergization is required when the thermostat reaches a predetermined upper temperature limit, and where electrical deenergization is re- -quired when the thermostat reaches a predetermined lower limit.

In operation, the user rotates shaft l5, by means of its knob, from the oil? position to the desired temperature setting. This swings the frames I0 and II away from each other about fulcrum means i2, usually a sufdcient amount to cause leverv25 to swing counterclockwise to the on position. This causes spring 50 and bar 52 to snap to the left and brings contacts 50 and 39 together to energize the heaters in the oven, as shown in dotted lines in Fig. 1. As the temperature in the oven rises, liquid flows from the thermostatic bulbin the oven through tube 23 to expand power element 2|. When the selected temperature is reached, the element 2| has ex' panded suiiicientiy to move lever 25 clockwise to a point where spring 50 and bar 52 snap to the right to the position shown in full lines in Fig. 1. This opens contacts 50 and 39, thus deenergizing the heaters in the oven. When the oven cools to the lower temperature limit, the element 2| contracts suiciently to snap the engagement with one of said 4 bar to the left. This starts the second heating cycle. which .may be repeated until the knob oi shaft I5 is turned to the ofi.' position.

While the form of embodiment of the invention as herein disclosed constitutes a. preferred form. it is to be understood that other forms might be adopted. as may come within the scope of the claims which follow.

What is claimed is as follows:

1,. A switch device comprising: a first frame; a second frame; fulcrum means holding said frames together; a snap acting switch on said first a thermostatic power element on said and engaging said snap acting manually movable element engaging said frames and adjusting the angle between said frames to vary the temperature setting.

2. A switch device comprising: .a first frame; a second frame; fulcrum means holding said vary the temperature setting.

3. A switch device comprising: a rst frame; a second frame; fulcrum means holding said frames together; a snap acting switch on said y st frame; a thermostatic Ipower element on said second frame and engaging said snap acting switch; and manually rotatable shaft in threaded engagement with one of said frames and in axially fixed bearing engagement with the other of said frames, rotation of said shaft adjusting the angle between said frames to vary the temperature setting.

4. A switch 'device comprising: a rst frame; a second frame; fulcrum means holding said frames together; spring meansv engaging said frames and tending to vary the angle between said frames; a snap acting switch on said rst frame; a thermostatic power element on said second frame and engaging said snap acting switch; a. manually rotatable shaft in threaded frames and in axial engagement with the other of said frames in opposition to. said spring means, rotation of said shaft ladjusting the angle between said frames to vary the temperature setting.

5. A switch device comprising: a frame; a stationary contact secured' to said frame; a snap acting U-shaped conductor blade having a first leg secured to said frame and a second leg having its non-connected end portion in snapping engagement with said stationary contact; and movable spring means creating a longitudinal strain in said rst leg.

6. A switch device comprising: a frame; a stationary contact secured to said frame: a. snap acting U-shaiped conductor blade having a rst leg secured to said frame and la second leg having its non-connected end portion in snapping engagement .with said stationary contact; a lever fulcrumed on said frame; and spring means carried by said lever and connected to the yoke portion of said conductor blade to create a longitudinal strain in said first leg.

7. A switch device comprising: a frame; a stationary contact secured to said frame; a snap Aacting U-shaped Vconductor blade having a rst leg secured to said frame and a second leg having its projecting non-connected end portion in to swing in one direction: a movable. element engaging said lever to urge said lever in the opposite direction; and spring means carried by said lever and connected to the yoke portion of said conductor blade to create a longitudinal strain on said rst leg.

8. A switch device comprising: a frame; a sta- .tionary contact secured to said frame; a snap acting U-shaped conductor blade having a rst leg secured Ato said frame and a second leg having its. projecting non-connected end portion in snapping engagement with said stationary contact; .a lever fulcrumed on said frame; a thermostatic element engaging said lever to swing said lever in response to temperature conditions; and spring means carried by said lever and connected to the yoke portion of said conductor blade to create a longitudinal strain on said ilrst leg.

9. A switch device comprising: a first frame;

a stationary contact secured to said frame; a..

snap acting U-shaped conductor blade having a first leg secured to saidlframe and a second leg in snapping engagement with said stationary contact; a lever fulcrumed on said frame; spring means carried by said said conductor blade to create a longitudinal strain on said first leg; a second trame; fulcrum means holding vsaid frames together; a thermostatic element carried by said second frame and engaging said lever to swing said lever in response to temperature conditions; and means to vary the angle between said frames to adjust the temperature'setting.

10. A switch a stationary contact secured to said frame; a snap acting U-shaped conductor blade having a rst leg secured to said frame and a second leg in snapping engagement with said stationary contact; a lever fulcrumed on said frame; spring means carried by said lever said conductor blade to create a longitudinal strain on said r'st leg; a second frame; fulcrum means holding said frames together; a thermostatic element carried by said second frame and engaging said lever to swing said lever in response to temperature conditions; and a manually rotatable shaft engaging said frames and adjusting the angle between said frames by rotation of said shaft to vary the temperature setting.

11. A switch device comprising: a iirst frame; a stationary` contact secured to said frame; a snap acting U-shaped conductor blade having -a first leg secured to said frame and a second leg in snapping engagement with said stationary contact; aalever fulcrumed on said irame; spring means carried by said lever and connected to said conductor blade to create a longitudinal strain on said first leg; a second frame; iulcrum means holding said frames together; a thermostatic element carried by said second frame and engaging said lever to swing said ,lever in response to temperature conditions; and a manually rotatable shaft in threaded engagement with one 'of said frames and in axially iixed bearing engagement with the other of said frames, rotation of said shaft adjusting the'angle between said frames to vary the temperature setting.

12. A switch device comprising: a first frame; a stationary contact secured to said frame; a snap acting U-shaped conductor blade having a nrst leg secured to said frame and a second leg in snapping 'engagement with said stationary contact; a lever fulcrumed on said frame; spring means carried by said lever and connected to 'said conductor blade to create a longitudinal strain ductor blades each having lever and connected to I device comprising: a first frame;

and connected to -6 on said` first les; a second frame; iuicrum means holding said frames together; a thermostatic element carried by said second frame and engag.

' ing said lever to swing said lever in response tc a second leg having temperature conditions; second spring means engaging said frames and tending to vary the angie between said frames; a. manually rotatable shaft in threaded engagement with one oi said frames and in axial engagement with the other of said frames in opposition to said second spring means, rotation of said shaft adjusting the angle between said frames to vary the temperature setting.

13. A switch device comprising: a frame; a plurality oi stationary contacts secured to said frame; a plurality of snap acting U-shaped cona ilrst leg with its nonconnected end portion secured to said frame and its non-connected end portion in snapping engagement with a different one of said stationary contacts; a bar bridging said lblades* to cause 'simultaneous motion of said spring means applying a the yoke portion of the longitudinal strain on said blades; and movable column loading upon ilrst legs for creating ilrst legs.

14. A switch device comprising: a frame; a plurality of stationary contacts secured to said frame; a. plurality of snap acting U-shaped conductor bladeseach having a rst leg secured to said frame and a second leg in snapping engagement with a respective one of said stationary con,- tacts; a bar bridging said blades to cause simultaneous motion oi! said blades; a lever fulcrumed on said frame; and spring means carried by said lever and connected to said conductor blades to create longitudinal strain on said iirst legs.

15. A switch device comprising: a frame; a plurality of stationary contacts secured to said frame; a plurality of snap acting U-shaped conductor blades each having a iirst leg ,secured to. said frame and a second leg in snapping engage- VVment with a respective one of said stationary said frame contacts; a bar bridging said blades to cause simultaneous motion of said blades; a lever fulcrumed on said frame; a engaging said lever to swing said lever in response to temperature conditions; and spring.

means carried by a said lever and connected to said conductor blades to create a longitudinal strain on said first legs.

16. A switch device comprising: a iirstirarne; a plurality of stationary contacts secured to said trame; a plurality of snap acting U-shaped con. ductor blades each'having a first leg secured to and a second leg in snapping engagementv with a respective one of said stationary contacts; a bar bridging said blades to cause simultaneous motion o! said blades; a lever fulcrumed on said frame; spring means carried by said lever and connected to said conductor blades to create a longitudinal strain on said first legs; a second trame; iulcrum means holding said frames together;` a thermostatic element carried by said second frame and engaging said lever to swing saidlever in response to temperature conditions; and means to vary the angle between said frames to adjust the temperature setting.

1'1. A switch device comprising: a nrst frame; a plurality of stationary contacts secured to said trame; a plurality of snap acting U-shaped conductor`blades each having a first leg secured to said frame and a second leg in snapping engagement with a respective one of said stationary'contacts; a bar bridging said blades to cause simulthermostatic element.

taneous motion of said blades; a lever fulcrumed on said frame; spring means carried by said lever and connected to said conductor blades to create va longitudinal strain on said first legs; a second frame; fulcrum means holding said frames together; a thermostatic element carried by said second frame and engaging said lever to swing saidlever in response to temperature conditions; and a manually rotatable shaft engaging said frames and adjusting the angle between said frames by rotation of said shaft to vary the temperature setting.

18. A switch device comprising: a rst frame; a plurality of stationary contacts secured to said frame; a plurality of snap acting U-shaped conductor blades each having a rst leg secured to said frame and a second leg in snapping engagement with a respective one of said stationary contacts; a bar bridging said blades to cause simultaneous motion of said blades; a lever fulcrumed on said frame;v spring means carried by said lever and connected to said conductor blades to create a. longitudinal strain on said first legs; a second frame; fulcrum means holding said frames together; a thermostatic element carried by said second frame and engaging said lever to swing said lever in response to temperature conditions;

lsecond spring means engaging said frames and tending to vary the angle between said frames; a manually rotatable shaft in threaded engagement with one of said frames and in axial engagement with the other of said frames in opposition to said second spring means, rotation of said shaft ad-` justing the angle between said frames to vary the temperature setting.

19. A switch device comprising: a frame; an

snap acting U-shaped conductor bar having the non-connected end portion of its second leg in off and on contact with said stationary contact;

i and spring means creating an on and oi bias in 8 means acting upon the bridging means for imposing a column loading upon the two anchored legs, two switch contact means insulated from each other each cooperating with the unanchored leg oi' one of said U-shaped members, and means for moving a portion of said spring means in a directo the column loading to cause one direction from the yoke with separate leg members connected to each anchorage, switch contact means cooperating with a remaining leg member, tension spring means having one end connected to said yoke and having the other end extending in generally the same direction as said anchored legs, and means for laterally moving said other end of said spring means to operate the movable member.

22. A control including a rst frame, a second frame, a fulcrum means pivotally connecting the frames together. a control device mounted on said rst frame, a power element mounted on said second frame and having means for engaging and operating said control device, and a manually movable element engaging said frames and adjusting the angle between said frames to vary the relationship between the change in dimension of the power element and the operation of the control device.

23. A control including a frame, a control device mounted upon said frame, a snap-acting U- shaped thin metal blade having the non-connected end portion of the rst leg secured to said frame and the non-connected end portion of its blade.

GEORGE C. PEARCE.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,960,020 McGall May 22, 1934 2,197,229 AWaddell Apr. 16, 1940 2,218,908 Fonseca s Oct. 22, 1940 2,239,438 Cockrell Apr. 22, 1941 

